The invention relates to the energy supply to elements supplied with voltage in motor vehicles, and, more particularly, but not exclusively, to the energy supply to elements of air-conditioning devices.
In addition to a motor-driven fan unit producing the blown airflow, the air-conditioning devices of motor vehicles comprise a number of elements operating under an energy supply, such as the actuators of air-mixing and distribution flaps, elements of the control panel for the air conditioning, and sensors, especially temperature probes.
In the usual way, the motor-driven fan, as well as the other elements of the air-conditioning device, are supplied from a main energy bus of the vehicle conveying the voltage from the battery.
With each element, a circuit has to be associated, having the purposes of:
carrying out filtering and protection against the electrical xe2x80x9cpollutionxe2x80x9d present on the main energy bus, and
delivering one or more regulated voltages for logic control circuits or analog interfaces such as interfaces for supplying windings of stepper motors, for example, constituting actuators of flaps.
The electrical xe2x80x9cpollutionxe2x80x9d is generally substantial in a vehicle: pulses, transient waves, overvoltages, breaks, electromagnetic interference, accidental polarity reversals, fluctuation, etc.
Furthermore, the supply of regulated voltage for logic circuits requires a change from a battery voltage of 12 V or 24 V, or even 42 V in the future, to a voltage of 5 V or less with new generations of components.
Even if filtering, protection and regulation circuits functioning satisfactorily under such conditions can be produced at low cost, they generate a substantial heat dissipation. The sophistication of air-air-conditioning devices requires an ever-increasing number of elements to be supplied with voltage. The overall cost of the filtering, protection and regulation circuits becomes not inconsiderable, and their total heat dissipation becomes very substantial which, when the air-conditioning device is operating in refrigeration mode, affects the usable cooling capacity.
The object of the invention is to remedy these drawbacks and, to that end, it proposes a unit for distributing energy to elements of an air-conditioning device or, more generally, to a number of elements supplied with electrical energy in a motor vehicle.
This unit includes an energy-supply input for receiving an input voltage, an energy output, and a voltage-regulation, protection and filtering assembly connected between the power-supply input and the energy output so as to deliver the same security-protected operating voltage to the said elements via an energy bus linked to the energy output.
Thus, with the various elements being connected to a security-protected energy bus, the electronic circuits for processing the received energy which are associated with these elements can be limited to circuits which may be present for step-down and regulation of voltages for the power supply to logic circuits or to particular analog interfaces.
The energy-distribution unit may further include an information input for connection to a first information bus, an information output for connection to an information bus specific to the said elements, and a monitoring circuit for transferring, on the specific information bus, the information relating to the said elements flowing on the first information bus, and conversely.
By virtue of this arrangement, the energy-distribution unit constitutes both an energy gateway and an information gateway between, on the one hand, an energy bus and an information bus of the vehicle and, on the other hand, an energy bus and a specific information bus.
Advantageously then, the monitoring circuit comprises means for distributing, in time, the energy distributed to the various elements, by time-shifting, as required, of the orders addressed to these elements via the specific information bus.
Thus an energy-distribution and management system is available, which makes it possible to limit the power to be delivered at any instant and thus the dimensioning of the voltage-regulation, protection and filtering assembly, and of the security-protected energy bus.
A further subject of the invention is a motor-vehicle air-conditioning device comprising a motor-driven fan unit and a number of elements supplied with voltage, the device comprising an energy-distribution unit as defined above and a security-protected energy bus linked to the energy output of the energy-distribution unit and powering the said elements.
The energy-distribution unit can be installed in the motor-driven fan unit, and more particularly in a motor-control module. It is then possible to make available, at the energy-supply input, the pre-filtered voltage supplied to the motor-driven fan. More particularly, the distribution unit receives a filtered voltage from a filtering circuit of the motor-control module of the motor-driven fan unit, while taking advantage of the airflow produced by the latter to remove the dissipated heat.
It is possible, however, to install the energy-distribution unit in the control panel for the air-conditioning, or in the form of an independent module.